Ofsted inspects and reports on anywhere that provides education for young people in England, including schools, nurseries and childminders.

Sir Martyn said it was “early days” since starting his role in January, but that he hopes to make a difference – referring to the suicide of head teacher Ruth Perry as a tragedy that should “never happen again”.

Mrs Perry took her own life while waiting for an Ofsted report and the coroner at her inquest ruled the inspection had “contributed” to her death.

Sir Martyn told delegates he did not apply for his job to allow for “business as usual”, but to bring change.

Over the next 12 weeks, Ofsted is asking parents and teachers to contribute to a consultation, external about how it should carry out inspections in future.

Mike Short, head of education at the Unison union, said Ms Keegan’s words were “not becoming of a government minister”.

“Making light of violence in schools when staff are increasingly likely to face assaults while doing their job is in very poor taste,” he said, adding that Ofsted inspectors “are already dealing with a great deal of hostility while they work”.

Last year, Ms Keegan had to apologise for her language after being caught swearing on mic as she expressed irritation over the concrete crisis in schools.